Sequence filling features of Middle-Late Devonian period in northern Youjiang basin

Abstract：Northern Youjiang passive continental margin rift basin developed NW-trending tensile synsedimentary faults and NE-trending strike-slip faults in Middle-Llate Devonian period. Guided by dynamics of sequence filling and combined with single profiles, profile correlation and plane changes, the authors analyzed filling material and evolution characteristics of sedimentary facies in the process of sequence filling. A study of the process of sequence filling reveals that there were two pulsing tectonic activities in each transgressive period and high stand period, with the trend of gradually increasing transgression, and intense extension in NE direction resulted in the formation of synsedimentary faults in NW direction which had time-ordered characteristics. The authors have confirmed that the platform-basin stretched into intra-platform and formed platform alternating with platform-basin. It is concluded that the time-ordered characteristics of tectonism resulted in the differentiation of the distribution of the sedimentary facies in different periods.